Many times the User picker will show name and on a smaller font it will show the email address, however in many other parts of the Jira system, this is not the case.

We see this happening in different scenarios, such as the watcher example below.

When I want to select a Watcher and type the name in the field, only the full name is shown and the email address isn't. 

This makes it hard to identify colleagues with identical names.

 I would like to request the email address and job title / department to be displayed when using a user picker field.

other scenarios are on a customer user picker field, on the Create screen it does not show email, but on the edit/view screen it does.

This ability should also be extended to other fields like Request Participants, Portal user picker fields, JSM Forms, comments, etc.